000
AXPZ20 KNHC 270921
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON FEB 27 2012
 
TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0830 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE ITCZ AXIS WAS ANALYZED FROM 01N124W 04N140W. NO SIGNIFICANT 
CONVECTION IT NOTED NEAR THE ITCZ.

...DISCUSSION...

THE 1038 MB SUBTROPICAL HIGH LIES N OF THE AREA NEAR 39N145W AND 
EXTENDS A RIDGE SOUTHEASTWARD TO 20N120W. TROUGHING OFF THE BAJA 
CALIFORNIA COAST HAS ERODED THE SOUTHEASTERN SIDE OF THE 
SUBTROPICAL RIDGE AND FORCED THE TIGHTEST PRES GRADIENT INTO 
NORTHWESTERN FORECAST WATERS WHERE FRESH NE WINDS WERE SAMPLED 
BY THE 0628 UTC ASCAT PASS. THIS PASS...ALONG WITH THE 0444 UTC 
ASCAT PASS...SHOW FRESH TRADES HAVE RETURNED FROM 09N TO 13N W 
OF 115W. 

A STRONG MID LEVEL LOW IS RACING SOUTHWARD OFF THE CALIFORNIA 
COAST. THIS LOW IS ASSOCIATED WITH A COLD FRONT THAT WILL PASS 
THROUGH THE NORTHERN GULF OF CALIFORNIA OVERNIGHT TONIGHT. AS 
THIS SYSTEM MOVES EASTWARD...THE SUBTROPICAL RIDGE WILL EXPAND 
EASTWARD IN ITS WAKE. FRESH NW WINDS BEHIND THE COLD FRONT WILL 
SPREAD SOUTHWARD ALONG THE BAJA CALIFORNIA COAST WHILE TRADES 
WILL EXPAND IN AREA S OF THE RIDGE AXIS. 

GAP WINDS...

GULF OF TEHUANTEPEC...AN OBSERVATION FROM SHIP PDGS AT 0800 UTC 
SHOWS THE GAP WIND EVENT IS CONTINUING IN THE GULF OF 
TEHUANTEPEC. WINDS WILL PULSE TO NEAR GALE FORCE IN THE EARLY 
MORNING HOURS WHEN MOUNTAIN DRAINAGE FLOW IS AT A MAXIMUM 
THROUGH TUE MORNING AND DIMINISH A NOTCH BY WED MORNING. 

GULF OF PAPAGAYO...A STRONG PRES GRADIENT ACROSS THE WESTERN 
CARIBBEAN AND CENTRAL AMERICA IS FORCING FRESH TO STRONG NE FLOW 
THROUGH THE GULF OF PAPAGAYO THAT IS EXPECTED TO CONTINUE 
THROUGH THE END OF THE PERIOD WED MORNING. IN ADDITION...MID 
LEVEL ENERGY EXTENDING DOWNWIND FROM PAPAGAYO IS ENHANCING NE 
WINDS AT THE SURFACE AS FAR W AS 97W BASED ON OBSERVATIONS FROM 
SHIP 9V8797 AND THE 0302 UTC ASCAT PASS. THESE WILL ALSO 
CONTINUE THROUGH THE PERIOD.

GULF OF CALIFORNIA...FRESH SW WINDS ARE EXPECTED IN THE NORTHERN 
GULF OF CALIFORNIA LATER THIS MORNING AHEAD OF A COLD FRONT 
ASSOCIATED WITH THE SYSTEM DROPPING S ALONG THE CALIFORNIA 
COAST. THE COLD FRONT WILL PASS THROUGH THE NORTHERN GULF 
OVERNIGHT TONIGHT. BY SUNRISE TUE...THE PRES GRADIENT WILL BUILD 
BETWEEN THE SUBTROPICAL RIDGE AND TROUGHING ASSOCIATED WITH THE 
COLD FRONT OVER MAINLAND MEXICO. N TO NW WINDS ARE EXPECTED TO 
REACH S OF 28N IN THE GULF TO AS FAR S AS 19N ALONG THE COAST OF 
MAINLAND MEXICO BY EARLY WED MORNING.

GULF OF PANAMA...FRESH TO STRONG NORTHERLY WINDS ARE CROSSING 
THE ISTHMUS INTO THE GULF OF PANAMA. SHIP PHSG NEAR 07N80W AT 
0300 UTC REPORTED 27 KT. THESE STRONG WINDS ARE EXPECTED TO 
CONTINUE INTO TUE AND DIMINISH TO FRESH BY EARLY WED MORNING.

$$
SCHAUER